Chrome Version       : 56.0.2924.87
URLs (if applicable) : N/A
Other browsers tested:
     Safari: OK (latest + Tech Preview Release 24)
    Firefox: FAIL (latest, bug here: https://bugzilla.mozilla.org/show_bug.cgi?id=1270636)
         IE: OK (Edge)

What steps will reproduce the problem?
(1) [OPTIONAL] Read up on the issue https://github.com/whatwg/console/issues/26
(2) Open up DevTools on any page
(3) Run either

console.time();
console.timeEnd(undefined);
console.log('Should see "default: XXXms"');

or

console.time(undefined);
console.timeEnd();
console.log('Should see "default: XXXms"');

in the console to see how passing `undefined` to either time/timeEnd does not trigger the default parameter outlined by the spec (link in next para).

What is the expected result?

The IDL in the console specification (https://console.spec.whatwg.org/#console-namespace) indicates that both time()/time(undefined) should behave the same along timeEnd()/timeEnd(undefined) such that a timer with label `default` gets started/stopped.


What happens instead?

It is instead clear that passing undefined in as a parameter to either of these functions actually converts it to the string "undefined" in Chromium, thus not falling back to the default timer label parameter value.


Please provide any additional information below. Attach a screenshot if
possible.

Again, more information on this and a conversation between me and Domenic Denicola can be found @ https://github.com/whatwg/console/issues/26.